1. Field of the Invention
The present invention relates to image display in a video game machine, and more particularly to a video game machine for reducing data volume and operation volume when a model whose texture changes is displayed on a TV screen, and improvements in the method for changing texture of the model.
2. Description of the Related Art
In video game machines, there is a need to change the texture of the surface (surface pattern, surface state) of objects and characters located in a virtual space. For example, the pattern on a surface of a xe2x80x9cchameleonxe2x80x9d may be changed in a game such that the pattern merges with surroundings, or a xe2x80x9crockxe2x80x9d may be changed into a precious stone.
One method for obtaining such an image effect is to create multiple steps of a large volume of texture data which changes continuously from a texture 1 of design A to a texture 2 of design B, which is different from texture 1, using a graphics computer, and storing the data in an image database. This database is stored in a large-capacity storage medium, such as a CD-ROM, along with game programs. At a relevant scene in the game, the model data and texture data are read, and a series of textures wherein the design changes in steps are successively pasted onto the surface of the model, so that a texture model which looks as if it is continuously changing from one state to another state is created.
However, when the texture is changed from one state to another state, if it changed slowly, the number of frames of an image increases and the texture pattern data to be prepared becomes huge in volume. The similarly shaped models for applying texture are required in equal number to the number of texture patterns.
Furthermore, texture can be changed only for the number of change steps of the patterns for which texture has been prepared. This means that for each change in the number of frames to be synthesized or the game proceeding selection, a corresponding change pattern is required.
Therefore, the game machine must hold (memorize) a huge volume of pattern data, and requires a high processing capability to create many models in a short time.
A first object of the present invention is to provide a game machine that can create a model whose texture changes with a relatively small volume of image data.
A second object of the present invention is to provide a game machine that can create a model whose texture changes with a relatively small operation volume.
A third object of the present invention is to provide a method for changing texture of a three-dimensional model that even a CPU with a low processing capability can process.
In order to achieve the aforementioned objects, a video game machine in accordance with the present invention comprises: memory means for memorizing first and second models which are defined with shape and texture; model synthesizing means for obtaining a synthetic model by synthesizing the first model and the second model with a first transparency and second transparency respectively; transparency changing means for changing the first and second transparency complementarily; and display means for displaying the synthetic model on a screen of a monitor.
A further video game machine in accordance with the present invention comprises: memory means for memorizing first and second models which are defined with shape and texture; model synthesizing means for obtaining a synthetic model by overwriting (superimposing) the second model on the first model with a specified transparency; transparency changing means for changing the transparency continuously; and display means for displaying the synthetic model on a screen of a monitor.
According to a video game machine composed in this way, texture morphing can be implemented with a relatively small image data volume and small operation volume.
Preferably, the transparency changing means determines the amount of change of the transparency according to the number of frames of the synthetic model to be displayed on the monitor.
Preferably, the first and second models have the same image. This allows morphing to be implemented wherein the texture of the model changes from one texture to the other without changing the shape of the model.
Preferably, the first and second models have a common shape in each frame, but the shape is different between adjacent frames. This allows morphing to be implemented wherein both the shape and texture of the model change.
A method for changing texture of a model in accordance with the present invention comprises the steps of: memorizing first and second models which are defined with shape and texture; setting a first and second transparency for the first and second models respectively; correcting the first and second models with the first and second transparency respectively and synthesizing both of the corrected models; displaying the synthetic model on a screen of a monitor; and repeating the first to fourth steps while changing the first and second transparency complementarily. This method allows a model to be obtained whose texture changes, with a relatively small image data volume and small operation volume. Another method for changing texture of a model in accordance with the present invention comprises the steps of: memorizing the first and second models which are defined with shape and texture; obtaining a synthetic model by overwriting the second model on the first model with specified transparency; displaying the synthetic model on a screen of a monitor; and repeating the first to third steps while changing the transparency continuously. This method allows a model to be obtained whose texture changes, with a relatively small image data volume and small operation volume.
An information recording medium of the present invention records programs for causing a computer system to function as one of the game machines described above.